1. Field of the Invention
The present invention relates to a radio receiver and, more particularly, to a radio receiver with a potentiometer as volume control.
2. Prior Art
Radio receivers with a potentiometer as volume control have been known for a long time. Customarily the actuation of a switch in the current supply is coupled with the volume control in such a way that by displacing the knob of the potentiometer to the left or lower stop the volume is reduced and thereafter the switch for the current supply is actuated.
However, radio receivers have been on the market for a long time, wherein the switch in the current supply and the volume control must be operated separately from each other. Furthermore, characteristically in motor vehicles the installed car radios are connected via a series connection of two switches to the current supply, namely the series connection of a switch in the ignition lock of the vehicle and of a switch on the instrument.
When turning the radio receiver off with a switch separate from the volume control, it is possible to unintentionally turn the volume control in the turned-off state to full volume, without this being noticed at first. When a radio receiver set in this manner is switched on, the reproduction of the received transmitter takes place at an undesired volume.
In connection with road traffic radio receivers it is known per se to raise the volume of a traffic report automatically to a preset volume if it had been switched to a low volume or even switched off by means of the potentiometer of the radio receiver.
The automatic tracking of the volume in accordance with the respective loudness of the driving noise in the interior of a motor vehicle has been a property of modern car radios for a long time.
Such radio receivers have microprocessors which receive digital control signals and digitally control an audio frequency regulator in the low frequency state.